For one of our innovative projects, we have installed on a Raspberry Pi mod. B+ an HC-05, a Bluetooth module very useful for communicating with an Android app. Installing and configuring the HC-05 was very fast and rewarding. As you can see, it works! Here is his “Hello World!”.
The only flaw: it is not visible to Apple devices (iPhone, iPad, etc.). Due to some Apple company policies, their new devices only support Bluetooth 4.0, a.k.a. BLE (Bluetooth Low Energy). So, if you want to create an innovative device with a BT module also visible for Apple devices, you have to buy a BLE module, like the HM-10. 🙂